Stem Cell Core B is directed by Drs. Sorrentino and Persons and provides for stem cell procurement, processing, and manipulation for both the preclinical and clinical trial procedures within this application. Dr. Persons will direct the preclinical activities in this Core which include purification and transduction of nonhuman primate cells as outlined in Project 1 as well as purification of mouse hematopoietic stem cells from murine SCD and WAS models in support of Projects 1 and 2. The Core will continue to define optimal lentiviral transduction conditions for CD34+ cells obtained from human bone marrow and G-CSF mobilized peripheral blood cells from normal volunteers. Transduction efficiencies will be determined using standard in vitro assays such as flow cytometry and CFU-C assays and also by reconstitution experiments in immunodeficient NOG mice. In addition to these preclinical and developmental functions, Core B will provide for the processing and transduction of clinical material obtained from St. Jude patients and used for the WAS clinical trial proposed in Project 2 and the LVXSCID trials in Project 3. These activities will be directed by Dr. Sorrentino. Patients treated on the LVSCID-OC trial at NIH will continue to use existing resources at the NIH clinical center under the direction of Dr. Malech and his colleagues and no funds are requested for these activities. For St. Jude patients, mobilized peripheral blood cells or bone marrow cells from patients will be collected, CD34+ cells will be obtained using a certified procedure based on the CliniMacs apparatus, cells will be transduced with certified vector supernatants prepared in our GMP facility, and processed cells will be prepared for injection into the patient. All of these clinical manipulations will be done in the St. Jude Human Applications Laboratory (HAL), which is an established clinical laboratory that supports all activities that are ongoing in the Division of Bone Marrow Transplant and Cell Therapy. Because of this expanded scope and emphasis on clinical trials, the activities and budget for the Stem Cell Core have increased from the past funding period.